// Copyright (c) 2019-2023 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module log

import os
import time

// Log represents a logging object
pub struct Log {
mut:
    level         Level
    output_label  string
    ofile         os.File
    output_target LogTarget // output to console (stdout/stderr) or file or both.
pub mut:
    output_file_name string // log output to this file
}

// get_level gets the internal logging level.
pub fn (l &Log) get_level() Level {
    return l.level
}

// set_level sets the logging level to `level`. Messges for levels above it will skipped.
// For example, after calling log.set_level(.info), log.debug('message') will produce nothing.
// Call log.set_level(.disabled) to turn off the logging of all messages.
pub fn (mut l Log) set_level(level Level) {
    l.level = level
}

// set_output_level sets the internal logging output to `level`.
[deprecated: 'use .set_level(level) instead']
[deprecated_after: '2023-09-30']
pub fn (mut l Log) set_output_level(level Level) {
    l.level = level
}

// set_full_logpath sets the output label and output path from `full_log_path`.
pub fn (mut l Log) set_full_logpath(full_log_path string) {
    rlog_file := os.real_path(full_log_path)
    l.set_output_label(os.file_name(rlog_file))
    l.set_output_path(os.dir(rlog_file))
}

// set_output_label sets the `label` for the output.
pub fn (mut l Log) set_output_label(label string) {
    l.output_label = label
}

// set_output_path sets the file to which output is logged to.
pub fn (mut l Log) set_output_path(output_file_path string) {
    if l.ofile.is_opened {
        l.ofile.close()
    }
    l.output_target = .file
    l.output_file_name = os.join_path(os.real_path(output_file_path), l.output_label)
    ofile := os.open_append(l.output_file_name) or {
        panic('error while opening log file ${l.output_file_name} for appending')
    }
    l.ofile = ofile
}

// log_to_console_too turns on logging to the console too, in addition to logging to a file.
// You have to call it *after* calling .set_output_path(output_file_path).
pub fn (mut l Log) log_to_console_too() {
    if l.output_target != .file {
        panic('log_to_console_too should be called *after* .set_output_path')
    }
    l.output_target = .both
}

// flush writes the log file content to disk.
pub fn (mut l Log) flush() {
    l.ofile.flush()
}

// close closes the log file.
pub fn (mut l Log) close() {
    l.ofile.close()
}

// log_file writes log line `s` with `level` to the log file.
fn (mut l Log) log_file(s string, level Level) {
    timestamp := time.now().format_ss_micro()
    e := tag_to_file(level)
    l.ofile.writeln('${timestamp} [${e}] ${s}') or { panic(err) }
}

// log_cli writes log line `s` with `level` to stdout.
fn (l &Log) log_cli(s string, level Level) {
    timestamp := time.now().format_ss_micro()
    e := tag_to_cli(level)
    println('${timestamp} [${e}] ${s}')
}

// send_output writes log line `s` with `level` to either the log file or the console
// according to the value of the `.output_target` field.
pub fn (mut l Log) send_output(s &string, level Level) {
    if l.output_target == .file || l.output_target == .both {
        l.log_file(s, level)
    }
    if l.output_target == .console || l.output_target == .both {
        l.log_cli(s, level)
    }
}

// fatal logs line `s` via `send_output` if `Log.level` is greater than or equal to the `Level.fatal` category.
// Note that this method performs a panic at the end, even if log level is not enabled.
[noreturn]
pub fn (mut l Log) fatal(s string) {
    if int(l.level) >= int(Level.fatal) {
        l.send_output(s, .fatal)
        l.ofile.close()
    }
    panic('${l.output_label}: ${s}')
}

// error logs line `s` via `send_output` if `Log.level` is greater than or equal to the `Level.error` category.
pub fn (mut l Log) error(s string) {
    if int(l.level) < int(Level.error) {
        return
    }
    l.send_output(s, .error)
}

// warn logs line `s` via `send_output` if `Log.level` is greater than or equal to the `Level.warn` category.
pub fn (mut l Log) warn(s string) {
    if int(l.level) < int(Level.warn) {
        return
    }
    l.send_output(s, .warn)
}

// info logs line `s` via `send_output` if `Log.level` is greater than or equal to the `Level.info` category.
pub fn (mut l Log) info(s string) {
    if int(l.level) < int(Level.info) {
        return
    }
    l.send_output(s, .info)
}

// debug logs line `s` via `send_output` if `Log.level` is greater than or equal to the `Level.debug` category.
pub fn (mut l Log) debug(s string) {
    if int(l.level) < int(Level.debug) {
        return
    }
    l.send_output(s, .debug)
}

// free frees the given Log instance
[unsafe]
pub fn (mut f Log) free() {
    unsafe {
        f.output_label.free()
        f.ofile.close()
        f.output_file_name.free()
    }
}